(a) Field
Exemplary embodiments of the invention relate to a backlight unit for a display device and a driving method thereof, and particularly, to a backlight unit for a display device, in which a light beam spread angle is effectively regulated, and a driving method thereof.
(b) Description of the Related Art
Generally, a display device includes a plurality of pixels for displaying an image, a display panel on which a signal line for transferring a driving signal to a pixel is provided, and a driver that generates a driving signal for driving the pixels.
The display panel includes a display region, which is a region for displaying an image, and a non-display region, in which the image is not displayed, and the non-display region includes a peripheral region around the display region, the pixels and signal lines may be positioned in the display region, and an end portion of the signal line may extend to the peripheral region.
The driver includes a data driver that applies a data voltage to the pixel and a gate driver that applies a gate signal for controlling the transfer of the data voltage. The gate driver and the data driver may be mounted in a chip form on a printed circuit board (“PCB”), a flexible printed circuit film or the like, for example, to be connected to the display panel, or a driver chip may be directly mounted on the display panel.
A display device may be a self-light emitting type display device that emits light by itself, such as a light emitting diode display (“LEDD”), a field emission display (“FED”), a vacuum fluorescent display (“VFD”), and a plasma display panel (“PDP”), or a light receiving type display device that does not emit light by itself but includes a light source, such as a liquid crystal display (“LCD”) and an electrophoretic display.
A display device including a separate light source, or the light receiving type display device, may be a transmission type display device, and the transmission type display device may include a display panel that displays an image and a backlight unit that supplies light to the display panel. The backlight unit typically includes a light source module for emitting light, various optical sheets, and the like, for example. The light source module may include at least one light source (or called a light emitting element). The light source may be a cold cathode fluorescent lamp (“CCFL”), a flat fluorescent lamp (“FFL”), a light emitting diode (“LED”), or the like, for example. Recently, an LED, which has small power consumption and small caloric value, has been widely used as a light source.
The backlight unit may be classified into a direct type backlight unit, an edge type backlight unit, and the like according to the position of the light source module. Among the various types of the backlight unit, the edge type backlight unit adopts a method of indirectly radiating light diffused through a light guiding plate on a display panel while the light source module is provided to one side or both sides of the light guiding plate.